Method of treating railroad track members



Aug. 29, 1933. Q DALEY METHOD OF TREATING RAILROAD TRACK MEMBERS FiledMay 8, 1931 Z jqVENTO 2Q; ATTORNEY Patented Aug. 29, 1933 UNITED STATESMETHOD OF TREATIN G RAILROAD TRACK MEMBERS Charles ArDaley Hornell, N.ill, assignor to Air Reduction Company, Incorporated, New York, N. Y., acorporation of New York Application May 8, 1931. Serial No. 535,863

2 Claims.

In order to prevent or reduce this wear, it hasbeen proposed to hardenthe tread portions of the rails, for a short distance from each end andto a moderate depth, by locally heating these regions above the point ofdecalescence by means of the oxyacetylene flame, and thereupon quenchingthe rail ends with water. In the course of study and experiment inconnection with this track problem I have found that such a treatmentdefeats its purpose, since strains are set up which cause the treatedportions of the rail to chip and spallf producing a condition worse thanthe normal wear. I

The wearing down of rail ends is to a large extent due to the cold flowof the metal caused by load on the rails exceeding the elastic limit.When trains pass over a rail the concentrated load applied under thewheels produces at times a stress greater than the elastic limit of thesteel in the rail. At any point between the ends of the rail this wouldtend to produce a permanent deformation were it not that the metal atthe bearing point is always backed up by a mass of metal at both sides.At the ends of the rail the effect of cold flow becomes in time verynoticeable, and its results are not only a lowering of the surface butalso a breaking away of material from the tread ends due to the lippingover of the metal and the working of these lips against each other astheends move up and down.

The object of this invention therefore, is to raise the elastic limit ofthe tread portions of the rails or other track members, at and adjacenttheir ends, suificiently to overcome or greatly reduce the cold iloweffect, thereby minimizing batter and materially prolonging the life ofthe rails, while at the same time purposely avoiding the production ofany high degree of hardness. It will be understood that the elasticlimit of the metal can not be raised without increasing the hardness,butin my process of treating'rail ends hardnesstis a concomitant ratherthan the objective and is rigorously limited. 7

By playing the flame of the oxyacetyleneltorch on the end portions ofthe tread surface until a tread surface layer is heated locallywell'above the transformation range, quenching the rail ends underproper control, and then drawingthe temper, I find that I can raise theelastic limit of the steel to an extent giving very useful resultswithout danger of causing the rail ends to crack or spall. For rails ofordinary composition (carbon about 0.70 %0.85%) "it is important thatthe heat treatment of the tread surfaces of the ends of the trackmembers be not allowed to result in a hardness much above a Rockwellhardness of 040-015. By conducting the operation so as to produce asuperficial hardness of approximately this value, the elastic limit ofthe metal in the treated regions is raised suificiently to stop or verygreatly retard the flow of metal at the ends of the rails, and withentire safety that the rail ends will not develop failure as the resultof the heat-treatment. The conditions of the control are variable andcanscarcely be speci- 7O fied but will be readily practiced by thoseskilled in the art when the object to be attained and the permissibledegree of hardening is kept in mind. a

The heat treatment of the top of the rail end is to be accomplishedquickly, so as to avoid altering the structure of the body of the railend, for which reason the oxyacetylene flame played on top of the railends is particularly efiective, but other means of heating may beemployed. The tread surface of the rails is heated above the point ofdecalescence to a depth of about one-quarter of an inch and for adistance of a few inches backof the adjoining or approxi- "mate ends ofthe rails, and as soon as this is accomplished the heated regions arequenched with water down to about 300 F. and then reheated to about 650F. This re-application of heat, by which the treated regions arereheated to a much lower temperature than before is necessary in orderto draw the temper at the very end of the top surface of the rail,without which chipping would result.

Rail ends are so treated in accordance with this process as to wear downpractically uniformly with theuntreatedjmajor' portions of the rail.Rail batter being the amount of depression of they running surface atthe ends as compared with the remaining running surface of the rail, itfollows that if the whole length of the rail wears down uniformly nobatter will exist. It is a purpose of this invention to raise theelasticity and hardness of the metal of the tread at the rail ends justsufficiently to retard the cold flow at these regions and to enable themto resist the hammer blows of the car and engine wheels passing from onerail to the other, to an extent which keeps the ends of the rail fromwearing down more rapidly than the tread of the main part of the rail.

In the accompanying drawing:

Fig. 1 is a side elevation of the ends of two rails at a joint in thetrack; and

Fig. 2 is an end elevation of one of the rails, the views indicatingschematically by dotted and shade lines the approximate extent and depthof the treated areas.

In these views the rails are marked 2, and the heat-treated regions aremarked 3.

It is contemplated that the rails will be subjected to the treatmentwhile in place in the track, but the rail ends may be given the treat-.ment before they are laid or at the mill where they are produced.

The method is equally applicable in connection with the building up ofworn rail ends by depositing metal under fusion on the worn ends, as bymeans of the oxyacetylene torch and welding rod. In such event, thetreatment would be applied to the rail ends after having been restoredin this manner.

It will be understood that rail steels of different compositions willrequire somewhat different control of time, temperature and volume ofcooling medium, and that different sizes of rails will also requiresomewhat different control, these matters being within the skill of theoperator. When worn rails are built up, the precise conditions ofcontrol in the treatment of the built-up rail ends will also depend tosome extent on the composition of the metal which has been added.-

the critical range of the steel, at and adjacent the ends only,quenching the heated regions to about 300 F., and then reapplying heatto the said portions so that they are reheated to about 650 F.,substantially as and for the purpose setforth. 7

2. A method of treating the ends of railroad rails in the track, whichcomprises quickly heating the upper tread portions of the same above thecritical range of the steel, at and adjacent the ends only, by localapplication of a torch flame, quenching the heated regions to about 300F., and then reapplying' the torch flame tothe said portions so thatthey are reheated to about 650? F., substantially as and for the purposeset forth.

CHARLES A. DALEY.

